Self-leveling form stake

ABSTRACT

A form stake for use in securing wooden forms around an area of concrete to be poured. The stake has a flat body with a T-shaped flange structure protruding from its front face, while the rear face of the stake is flat to slide smoothly against the face of the form as the stake is driven into the ground. The T-shaped flange structure has a central vertical rib terminating at the upper end of the stake in a horizontal driving shelf centered over the vertical rib. The driving shelf has a flat, uniform upper driving surface that forms the uppermost end of the stake. The driving shelf terminates at the flat rear face of the stake so that its upper surface can be driven level with the upper edge of the form using any non-specialized driving tool, at which point the stake tends to level itself with the upper edge of the form without being unintentionally driven below the upper edge of the form. The stake has holes for inserting fasteners through the stake into the form once the stake has been fully driven into the ground.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is in the field of stakes used to support concrete forms or barriers that are used along the outside of an area in which concrete is to be poured, so as to contain the poured concrete in that area.

2. Description of Related Art

Concrete form stakes are typically used to secure wooden boards or “forms” around the perimeter of a concrete pouring area, the stakes driven partway into the ground along the outside face of a form to hold it securely in place before, during, and after the pouring operation. Known stakes come in many shapes and sizes, for example homemade stakes made from scrap wood at the construction site as well as different types of commercial stake made from wood, plastic, and metal.

Another type of stake used in concrete pouring operations is known as a screed stake, used in spaced pairs to hold screed rods or bars in an even plane across the area to be poured to ensure that the concrete is level and smooth.

My earlier U.S. Pat. No. 6,588,164, issued Jul. 8, 2003, discloses a stake especially adapted for use as a screed stake, but which can also be used as a form stake. This screed/form stake has a flat rear face and a U-shaped upper cradle portion extending from the front face of the stake, the cradle designed to mate with a separate driver. The driver also has a flat rear face, and a screed-rod-shaped portion that extends from the front face of the driver to mate with a screed rod groove in the cradle portion of the stake. When the lower end of the driver is mated with the stake's upper cradle, the upper end of the driver serves as a pounding surface to drive the stake into the ground. The upper surface of the screed-rod-shaped portion of the driver can be used as a screed rod elevation-measuring surface when seated in the cradle, providing a platform for a transit to measure whether the stake has been pounded in far enough to support a screed rod at the proper height.

The screed/form stake has holes formed along its face for securing it to a concrete form with screws or nails. When used as a form stake, the stake is driven home with the same driver used for screeding operations, with the flat back of the driver allowing it to be used against the face of the form without interference. As shown in the patent, the stake can be driven to a point where its cradle is below the upper surface of the form. The stake is typically removed from the exterior face of the form after the concrete has been poured and has set.

BRIEF SUMMARY OF THE INVENTION

The invention is a stake designed specifically for use as a form stake. The stake can be pounded or driven into the ground with any non-specialized driving tool, such as a hammer or mallet or even a boot, and naturally levels itself at the top of the concrete form when pounded with such a tool. When the form is no longer needed, the stake can be easily pulled out of the ground with fingers or the claw of a hammer or tool.

The form stake has a relatively wide, flat body with a flat rear face, and a forward-facing T-shaped flange structure extending from the front face of the stake. The T-shaped flange structure has a horizontal driving shelf with a uniform, level impact surface at the top of the stake, and a central vertical rib section extending downwardly from the driving shelf with a depth equal to the depth of the shelf protruding beyond the face of the stake. The driving shelf forms the top surface of the stake. The vertical rib bisects the stake.

In a preferred form, the underside of the driving shelf has a predominantly perpendicular or acutely-angled surface on both sides of the central rib for grasping with the fingertips or hooking with a tool to pull the stake out of the ground.

Although the form stake is lighter and less expensive to manufacture than my previous screed/form stake, it is easier and faster and stronger to use as a form stake. These and other features and advantages of the invention will become apparent upon further reading of the specification, in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of two form stakes according to the invention, one prior to be being driven into the ground against a wooden form, and the other driven in level with the top of the form.

FIG. 2 is a front elevation view of a stake as shown in FIG. 1.

FIG. 3 is a side elevation view of the stake of FIG. 1, partially driven into the ground against the outside face of a concrete form.

FIG. 4 is a side elevation view similar to FIG. 3, but with the stake fully driven into position adjacent the concrete form.

FIG. 5 is a top plan view of the stake of FIG. 4 driven into the ground against the face of the form.

FIG. 6 is a side elevation view similar to FIG. 3, but shows the stake being pulled from its fully driven position by hand.

FIG. 7 is a side elevation view of a stake similar to the stake in FIGS. 1-6, but in which the depth of the T-shaped flange relative to the thickness of the stake body is shown in a preferred shallower configuration.

DETAILED DESCRIPTION OF THE INVENTION

Referring first to FIGS. 1 and 2, the invention is illustrated in a first illustrative example as form stake 10. Stake 10 is preferably molded as one piece from a suitably strong plastic material, for example a nylon or ABS plastic, although other plastics and materials such as wood or metal can be used, and although the stake is not limited to one-piece construction. Stake 10 is used to laterally secure a wooden form 12 in place around an area in which concrete 13 is to be poured. As shown in the Figures, stake 10 is driven into the ground with its rear surface against the outer face of form 12 to prevent the form from shifting during pouring or curing of the concrete against the opposite inner face of form 12.

Stake 10 has a flat body 16 with a front face 16 a bisected by a vertical center rib 18, a flat rear face 16 b, and angled or beveled lower edges 16 c terminating in a ground-penetrating point 16 d. The upper end of stake 10 is capped by a flat, horizontal driving shelf 22 perpendicular to vertical rib 18 and extending from the front face 16 a of the stake. Vertical rib 18 and driving shelf 22 accordingly form a forward-facing “T” on the front face of the stake.

As best seen in FIGS. 2 through 4, driving shelf 22 has a flat top surface 22 a, a flat bottom surface 22 b, a rear edge 22 c flush with the plane of the rear face 16 b of the stake, and a front edge 22 d that extends to the outer edge 18 d of vertical rib 18. Driving shelf 22 preferably extends fully to both sides of the body of stake 10 as illustrated.

The flat top surface 22 a of driving shelf 22 forms the upper end of the stake, with no thin wall or flange edges exposed, and with a surface area greater than the surface area of the cross-sections of center rib 18 and stake body 16. As best shown in FIG. 5, when stake 10 is viewed from above, the relatively wide, flat, upper face 22 a of driving shelf 22 is the only visible surface, overlying the cross-sectional areas or upper “edges” 16 e and 18 e of the stake body and center rib, and therefore presenting a uniform force-distributing face across the width of the stake. While a perfectly smooth, flat, uniform upper surface 22 a is preferred, it will be understood that minor variations such as different textures or surface finishes or patterns that leave the upper surface generally flat relative to the driving force and the top of the concrete form are acceptable.

Referring to FIGS. 3 and 4, stake 10 can be pounded into the ground with any non-specialized tool, for example the illustrated mallet 30, since the upper driving surface 22 a of the stake is a flat, wide, uniform force-distributing surface. No specialized driving tool is necessary, and, in soft soil, foot and even hand pressure (with body weight behind it) may be used to push against the relatively wide, even surface of the driving shelf. Driving the stake with non-specialized tools is accordingly both effective and comfortable, whether using a hammer, a mallet, a rock, a board, a boot, a hand, or any other convenient implement.

As best shown in FIGS. 1 and 4, stake 10 tends to automatically level itself both vertically and side-to-side at the upper surface 12 a of form 12, since a non-specialized driver (especially a driver with a driving or impact face wider than the depth of shelf 22) will tend to hit the upper surface 12 a of the form when the flat upper surface 22 a of driving shelf 22 is even with the upper surface of the form. Assuming that the overall length of stake 10 allows a sufficient portion of the stake to be driven into the ground for good holding power relative to the ground, leaving the stake's upper end 22 approximately even with the upper edge of form 12 provides the strongest possible support for the form. Leaving the upper surface of the stake 10 even with the top of form 12 also ensures that concrete smoothing tools can be run across the top of the form without interference. The overall jobsite is also given a neater, more professional appearance with all form stakes driven in evenly against the forms. And the risk of overdriving the form stake to a point where it becomes difficult to remove from the ground is reduced or eliminated.

Referring next to FIG. 6, stake 10 is also easily pulled out of the ground when the concrete forming operation is done. The lower or undersurface 22 b of driving shelf 22 is preferably perpendicular to the face of the stake so that maximum pulling force can be exerted on the stake through the shelf with the fingers or a tool hook or claw, as shown. The lower surface 22 b can also be angled inwardly at an acute angle to the front face of stake 10, as shown in phantom lines at 22 b′, for an even better hooking action on the shelf when the stake is being pulled from the ground. While the lower surface 22 b is preferably flat and uniform as shown, it is possible to vary the contour so long as significant gripping or hooking portions are perpendicular or acute.

Holes 24 in the face of stake 10 allow the stake to be secured to the face of the form in known manner, for example with nails or screws driven through holes 24 into the face of form 12.

It will be understood that the length and width and relative dimensions of stake body 16 can vary according to the anticipated height of the forms with which it will be used, the nature of the ground into which it will be driven, and the weight or force of concrete that is anticipated against the form. Although the protruding T-shaped flange formed by center rib 18 and driving shelf 22 is shown as extending relatively far from the front face 16 a of the stake body in FIGS. 1-6 for purposes of illustration, it will be understood that the dimensions can vary here as well, and that in general the distance the T formed by rib 18 and shelf 22 protrudes from the face of stake 10 can be relatively small without affecting stake performance, and making form stake 10 lighter, less expensive, stronger, and easier to store and ship. In a most preferred form shown in FIG. 7 as stake 10′, the distance that the T protrudes is approximately equal to the thickness of the flat stake body 16, for example on the order of ¼-inch for an eighteen-inch long, three-to-four-inch wide stake body.

While stake 10 is especially designed for use as a form stake, it may find use in other applications for providing good holding power against significant forces in loose soil or sand or even snow.

While the illustrated embodiment shows the body of stake 10 reinforced and guided by a single central vertical rib 18, it will be understood that a plurality of ribs centered on a vertical section of the front face of the stake to symmetrically divide it can also be used.

It will be understood that the disclosed embodiment is representative of a presently preferred form of the invention, but is intended to be illustrative rather than definitive of the invention. The scope of the invention is defined by the following claims. I accordingly claim: 

1. A form stake comprising a flat body with a front face, a flat rear face, an upper end, and a lower ground-penetrating end, the front face having a protruding T-shaped flange structure comprising a central vertical rib section bisecting the front face of the stake and a horizontal driving shelf, the vertical rib terminating in the horizontal driving shelf, the driving shelf being perpendicular to and centered over the vertical rib, the driving shelf having a flat, uniform upper driving surface overlying both the upper end of the stake body and the vertical rib.
 2. The form stake of claim 1, wherein the driving shelf has a rear edge that terminates at the flat rear face of the stake body.
 3. The form stake of claim 1, wherein the stake includes a plurality of holes formed in the flat body, with at least one hole on each side of the central vertical rib section.
 4. The form stake of claim 1, wherein the driving shelf has a lower surface portion that is at least perpendicular to the flat body of the stake.
 5. The form stake of claim 4, wherein the driving shelf lower surface portion is acutely angled relative to the flat body of the stake.
 6. The form stake of claim 1, wherein the distance the driving shelf protrudes from the front face of the stake is equal to the depth of the center rib.
 7. The form stake of claim 6, wherein the T-shaped flange structure protrudes a distance from the front face of the stake approximately equal to a thickness of the stake body. 